REGCAP.EXE is a utility that can extract IDL information from a COM server 
into a .REG file. 
It was included with Visual Studio 2005 SP1. Because it 
is undocumented, To get efficient and effective answers on how to 
use it 
you'll have to contact Microsoft directly.

 

Regcap is a tool intended to aid in setup authoring, but by the very nature 
of the way it works, it’s not perfect.